FIGURE 2:

Characterization of the pyk2−, pyk3−, and double-null strains. (A) Hyperosmotic stress–induced activation of STATc in parental Ax2 and pyk2−, pyk3−, and double-null strains. Parental Ax2 cells and null cells were developed in shaken suspension for 4 h and then treated with sorbitol at 200 mM for the indicated times. Tyrosine phosphorylation of STATc was assayed by Western transfer, using phospho-STATc antibody CP22. The same blot was reprobed with total-STATc antibody 7H3 (unpublished data). The combined data from several such experiments are shown as fold relative to sorbitol-induced Ax2 (at 15 min) ± SD. Student's t test: *p < 0.05; **p < 0.01. (B) Nuclear enrichment of STATc in parental Ax2 and pyk2−, pyk3−, and double-null strains. Cells developed as in A were treated with sorbitol at 200 mM for 5 min. The nuclear accumulation of STATc was assayed immunohistochemically, using total STATc antibody. KK2 PB–treated cells were used as control, as it is the vehicle for sorbitol. Bar, 10 μm.